High ISO Compared: Sony A7S vs. A7R vs. Canon EOS 5D III

Introduction

Sony's A7-series lineup has garnered quite a lot of interest amongst camera enthusiasts, striking an appealing balance between image quality and size. Both the A7 and A7R bodies, as well as the native FE lenses Sony has recently introduced, are remarkably small and lightweight - especially when you consider the quality of images they're capable of producing.

The A7S is Sony's newest entry in its full-frame mirrorless lineup. But where the 'R' in A7R stood for resolution, the 'S' in the 12MP A7S stands for sensitivity. Furthermore, with its full-sensor readout and 4K video capabilities, the A7S is as much a camera for video as it is a camera for stills. And let's face it: there are very few videographers and photographers who wouldn't be thrilled by a camera offering higher sensitivity and impressive, low noise, high ISO performance.

Now, this purported increase in sensitivity comes at a cost: in the face of cameras with ever-increasing megapixels, the A7S comes in at a rather paltry 12MP. Lower resolution and higher sensitivity are certainly not unheard of - the Canon 1DX and Nikon D4S both top out at relatively modest resolutions of 18 MP and 16MP, respectively (though this is partly done in the name of speed). But is the resolution of a bygone era (Canon EOS 5D anyone?) a worthy tradeoff for the still image and video quality enhancements? Sony certainly seems to think so.

We just got our hands on an A7S, and have been busy putting it up against its competitors to see what advantages it offers and, quite frankly, to see if the claims regarding its low light performance are accurate. Particularly, some of us here have been curious as to whether not the increased ISO performance is significant enough to warrant the resolution tradeoff when the A7S is put up against its older sibling - the A7R.

Why make this resolution trade-off at all? Leaving aside video considerations (such as simplifying full sensor readout) for now, lower resolution sensors can increase pixel-level performance (because bigger pixels capture more light), but it's typically total light gathering area across the entire sensor that is a major determinant of ISO performance, all else being equal. So, to see whether the A7S offers anything beyond the pixel-level benefit its lower resolution would lead you to expect, the higher resolution image is normalized to the resolution of the lower resolution camera. Ultimately, for the A7S to make sense to stills as well as video shooters, Sony's engineers need to have exploited some of the other advantages that well-designed larger pixels can potentially bring *1.

The Shootout

We put the A7S up against the higher resolution A7R to see if the A7S offered any significant high ISO advantages over the A7R when the output of the A7R was downsized to that of the A7S. Furthermore, we pitted the A7S against a professional DSLR not too far outside the price range of the A7S. And so, we bring you this real-world comparison between the Sony A7S, Sony A7R, and Canon EOS 5D Mark III.

We shot a night scene that included a range of tones from deep shadows to bright highlights to get a comprehensive idea of noise performance of these cameras at various ISOs.

We waited until midnight to ensure minimal changes in ambient light during the course of our shoot (summer days are long in Seattle). In order to level the playing field for all three the cameras we did a few things:

Used the same lens (Canon 24-70 f/4L IS) for all cameras. A Metabones Smart Adapter III was used to fit the Canon lens on to the Sony bodies.

Aperture and shutter speed were matched across all cameras for any particular ISO setting.

RAW files were converted in ACR 8.5 to give relatively consistent rendering across cameras. This was done by manually selecting white balance per camera, and adjusting Shadow Tint as necessary at higher ISOs in order to avoid magenta-tinted blacks. Sharpening and noise reduction were left to ACR defaults (Sharpening: 25 | Luminance NR: 0 | Color NR: 25).

Since the A7R and 5D Mark III don't offer ISO sensitivity settings above 25,600 and 102,400, respectively, these higher ISO shots were simulated by maxing out the ISO on each respective camera, adjusting shutter speed, and then digitally boosting exposure in ACR to aid comparisons against the higher ISOs of compared cameras.

Do note, however, that (1) nobody in their right mind would boost high ISO JPEGs in this manner (it's preferable to digitally boost Raws over JPEGs), and (2) when we did boost the high ISO Raw files in ACR, significant noise resulted. This itself speaks to the value of the higher ISO modes on the A7S (if you need them, that is), but also indicates that a more careful balancing act of noise reduction, sharpening, and exposure boosting would be more appropriate to obtain the 'simulated' higher ISO values than by simple (digital) exposure boosting.

Without further ado, let's get to the comparisons. Below and on the next page you'll find a variant of our typical studio scene widget. Have a play with it (further instructions after the widget), then view some of our specific thoughts on the comparison on the next page. By default we've set the widget below to compare the A7S vs A7R, but you can compare either camera to the Canon EOS 5D Mark III as well. And, as always, all files are available for download if you would like to tinker yourself.

Using the Widget

The widget above and on the next page is a variant of our typical studio scene widget. At the top is a drop down menu that allows you to select 'Normalized (12 MP)' or 'Native Resolution'. 'Native Resolution' indicates that images retain the maximum resolution the camera is capable of, whereas for the normalized analysis, images were downsized to 12 MP (using the bicubic resampling method).

As usual, we also have the Full, Print, and Web buttons at the top right of the widget. Full will maintain whatever you've selected in the top, center drop-down menu (12 MP for the normalized analysis, and full sensor resolution for the native resolution analysis). Print will downsize all images to 8 MP, while Web downsizes all images to 5 MP.

Remember that although the widget above starts with the Sony A7S pitted against the A7R, you can also compare the Canon 5D Mark III against either camera by selecting it in either drop-down menu.

Footnotes:

*1 For example, lowering cumulative sensor read noise, increasing effective sensor efficiency, and other factors that - to prevent this article sprawling - we won't elaborate upon further here.

i would get the A7s in a heart beat if it weren't for the lack of glassware. i looked into the lens adapters to use my canon lenses (and maybe buy a few nikon lenses, like the 85mm 1.4G) with the FF Sony cameras, but the ridiculously slow focusing with those adapters scares me away from moving to Sony mirrorless cameras... what to do?

I appreciate the study and comparison of the 3 cameras in the extreme lighting conditions. Is the performance at normal light levels worth talking about? The sensitivity of the A7s is a great feature for flexibility when needed, but is it comparable to the others in "more normal" use?

Yes, the A7S has noticeably less DR than the A7R at base ISO. Especially when you normalize (downsize the A7R to 12MP resolution). I suppose 'noticeably' will depend on your application, but if you shoot sunrise/sunset landscapes, you may very well notice it. The A7S is still a couple of stops better at base ISO DR than a Canon DSLR, but at least a stop worse than A7R, D800, etc.

It does, however, maintain higher DR at higher ISOs.

As to your last question, I'd say the biggest reasons I can think of to consider the A7S over the A7R would be:

Video features

Lack of shutter shock, which hurts sharpness of A7R files at long focal lengths (e.g. with the 70-200 FE) at certain shutter speeds

Completely electronic shutter makes for very nice silent shooting; the A7R has an extremely loud shutter (well, two shutter sounds when you take a photo). Although, the fully electronic shutter on the A7S comes at an additional DR cost - b/c of extra noise in the shadows when enabled.

Why is it people keep talking about the "poor" dynamic range of Canon's "outdated" sensors and are unable to use their eyes enough to see the DR of the 5D Mk3, particularly in terms of the highlights, is smoking the Sony? Particularly on those big tripod like things in the distance.

No. Those lights were turned off by the city of Seattle by the time I got to the 5D Mark III. The 5D Mark III has demonstrably lower low ISO DR than either Sony camera, though differences even out at higher ISOs. The A7S has higher ISO performance and higher DR than either camera at higher ISOs.

Perhaps an article is in order that correlates DxO data with visual, real-world results to dispel this lingering belief that somehow entirely valid measurements can be disproved simply by 'using your own eyes'.

Then it's not much of a comparison image is it? It happens to be the first part of the image that got magnified on my computer, I also note that other highlight areas (lighted windows) do not show "demonstrably" better DR in the highlight areas either. At least not on this sample. They are actually much of a muchness. Even the Seattle Tower light areas have a little more detail on the 5D. You guys shot the images. I didn't.

It is a comparison. It's just not a comparison of what you want it to be.

This test was not designed as a DR test. It was designed as a noise test.

The 5D III cannot magically have more highlight detail b/c of more DR. If it has any more highlight detail over the A7S, it'll likely be b/c of a small increase in sensor efficiency on the A7S that makes the A7S overexpose a bit more easily (since matched focal plane exposures were used).

Please don't misuse the contents of this article for a purpose it wasn't designed for, and then say it's not much of a comparison. It's not a DR comparison, it's a noise comparison between cameras receiving equivalent amounts of light at different ISOs.

It's not that there is MORE highlight detail, apart from that tower, which is a methodology issue. As evidenced by most of the windows and dark areas, I said there was no less shadow or highlight detail. Which you would expect with the differences in dynamic range so many bellyache about. The first function of cameras is to shoot photographs. Not test charts.

No one 'bellyaches' about huge differences in dynamic range between these cameras at high ISOs, and there was no shadow push at low ISOs so, once again, I have no idea why you're talking about some attribute this particular test shows absolutely nothing about.

You trying to talk about DR from this test is akin to drawing conclusions about the maximum speed of a car from a steering test. They're completely orthogonal.

I am a beginner here but this is what I noticed for the comparison b/w canon 5dm3 and A7S. The yellow colors are somewhere the red colors are more richer in case of Canon 5dm3. Also, some of the places A7S seems overexposed? where as 5dm3 managed it quite well. please see here http://www.dpreview.com/reviews/image-comparison/fullscreen?attr65_0=sony_a7s&attr65_1=sony_a7r&attr66_0=25600&attr66_1=25600&attr67_0=raw&attr67_1=raw&attr68=12mp&normalization=full&widget=119&x=0.7929017009570305&y=0.043870286340165855

What ISO are you speaking of? At 25600 the A7r is similar for example (slightly more noise but better detail, noise reduction should set them on par until that ISO). Would I sell pictures apart from web sized shots above ISO 12800 or 25600? I think not.

Well on the default setting of Dpreview 25600 the 5D wins. Detail in highlights and retains colour and better tonal gradation. I was intending to get the Sony thinking it a step up for low light but Sony look to have thrown heavier software at the problem on first look.Even at 6400iso the same can be seen, weak colour, no highlight detail and poor gradation, I was hoping for better from the Sony I think I'll stick with the 1Dx for low light.

With the Sony A7s there's less grain, and details blurry in the Canon's raw are clearer in the Sony's raws.

The 5DIII has bit more cyan and magenta banding at that ISO than the Sony.

Why don't you try the above test?

Anyhow the Canon 6D is also a better high ISO body than the 5DIII. And the 5DIII is considered by no one to be Canon's best high ISO camera--that's the 1DX. While the Sony A7s is likely Sony's best high ISO camera.

Canon makes it clear that the highest 2 ISO settings are different. They are extended settings only available through a menu. I believe this means that they are amplifying the extra 2x or 4x by software after digitisation, effectively moving up from bits 0..13 to 1..14 or 2..15. It seems impossible to obtain confirmation of this but it is very important to me as an astrophotographer. If it is as I described then the highest 2 ISO settings are doing nothing useful for me. I cannot reduce my exposure times in the expectation that I will still get more useful data. Equally importantly for your comparison: are Sony doing the same thing but not making it clear? Is anyone here able to confirm or refute my suppositions?

Hi grelf,I am curious too about the "expandable" ISO in the A7. Until then, from my own perception so far: Nex5 was best at iso 3200. I suspect sony is moving bits from 0-13 more likely to 9-15 when at 25600. Thus, I hope that A7r coul be good for Astro. Just considering the missing AA filter and better yet, cropping instead of using a Barlow on small objects. I also suspect that using bias files (short dark exposure file containing ADC read noise) will greatly reduce the a7s advantage over a7r. I use a canon 6D with a Baader filter and somehow, I suspect that a7r + crop > 6D + Barlow, if you are not shooting Andromeda or bigger objects. On a 2nd thought, I think I will just stay happy with 3200-6400 on the a7r after reading this article and analyzing the tests. Ah yes, I like sony more than other cameras for astro stuff but am no fanboy, Interested only in results.

Coming from the old analogue school i do not see the need of these high iso values....Even noise is not obvious at Iso 1600 for the A99 and not problematic until you set an Iso above 6400, I am just happy using the camera's highest and workable performance setting iso 1600-

When higher shutter speeds are needed to shoot a performance like ballet or dance at low light (and you would like to retain some DOF or sharpness by not opening the lens fully), every improvements in high iso noise are welcome!

Ditto what some have already pointed out. The difference will be huge in video. Someday somebody will make a consumer grade full frame 1080P video cam with exactly 1920 x 1080 pixels on the sensor. Or 4K video with only 4,096 x 2,160 pixels on the sensor.

Until then, this is the closest you can get.

I can imagine bringing both the A7R and A7S for work or travel. The former for daytime outdoor shoots and the latter for indoor/night time shoots and video. What a combo. It'll be like the old days when different film bodies were loaded with different speed film.

No one ever will make FF sensor for just fullHD. maybe 5 years ago this was bright idea, not anymore. For 4k there are several different resolutions and 12MP is very close. I will be very much surprised if someone will make lower MP camera but this is possible.

In good light, Foveon might work with exact 1920x1080 for FullHD, but Bayer-sensors don't have the full resolution their pixel count may indicate since the values for all R, G and B are obtained by interpolation from neigboring pixels, so their resolution should be higher, ideally 2x.

One thing to keep in mind is that inside A7s is sensor meant for Video cameras, not still photography. It's at video that it really shines. Fact that this also makes stills this good is a great bonus to the Sony name.That said, I am Sony fan(boy) and ditched canon for them because they tickle my gadget itch more than anyone else. Sony is at their best when they let their engineers run rampant and create all kind of thing. from Betamax and Walkman to this day they always improved and innovated (even if some standards lost their advantages really quickly like MemoryStick which speed got overtaken withing 12 months). But at the same time I feel like they are innovating themselves into corner and with so many new and innovative camera's and sensors (including announced curved ones) thy can't keep up with lenses. Especially compared to Caninkon competition. Also, their lenses, by economy of scale, tend to be more expensive while not being quite as good.

Exactly... after 5 yrs of Nikon, 15 yrs of Canon, my Sony A99 simply knocked Canikon out of the park.

Its not just any one thing - something the fanboys don't get.

Its not just the image-stabilised full frame sensor that gives me extra 3-4.5 stops on EVERY lens.Its not just the Carl Zeiss lenses.Its not just the total lack of mirror vibration so there is no blurring at handheld shots below 1/60th seconds.Its not just the lower noise so I can do theatre work better.Its not just the electronic 1st curtain and shutter release response time which is faster than the EOS 1DX.Its not just the Sony sensor tech that is found in cameras like Nikon, Olympus, Panasonic, Pentax, Phase One medium format.Its not just Sony sensor tech that is in Samsung/LG/Sony/Oppo smartphone.

... my LCD display cos I know the exact exposure/colour tone & temperature before I shoot. The LCD is permanently closed inwards & only opened when I need to shoot at the waist level or ground level.

Its ironic how these are also precisely the reasons that allow mirrorless camera users to take better pictures than many traditional pentaprism OVF relics. Try looking at the great work found on m4/3, NEX, Fuji, Alpha forums/interest groups (on a photographic technique level, not pixel peeping level).

@Pretern... Ridiculous statement to say mirror less users take better pictures imo. Handling of smaller mirror less has pros and cons. The mirror may introduce slap (easy to avoid with lock up), but the A7r and OMDs for example show that shutter vibration is an issue. I'm furthermore not so sure whether an EVF is that important. I use both mirror less and DSLR and with a little bit of experience you know which setting to take to not clip highlights, for example. For beginners it is nice, of course. It may be he future, but I don't have a problem with both.

I'm no fan of anything except innovation and technical excellence. Problem with you fans is that you don't get it cos you are too busy being a fan.

Of course the technical quality of the A99 shots are higher when I have up to 4.5 stops in-body image stabilisation advantage over any Canikon at focal lengths up to 70mm (with any lens). It is a MASSIVE GAME CHANGER. Even if you are half blind you can see the difference of 3-4 stops can't you?

I can take 1/8th s shots handheld with my Zeiss f2.8 16-35mm, 24-70mm lenses at ISO 800. Other photogs would have to shoot at 1/30th s & ISO 3200 (while suffering the full effects of mirror vibration blurring + mirror slap noise) during a theatre performance.

@FLM - Typical ridiculous ignorance of u folks with no understanding of photography. You dunno what mirror slap is but you make ignorant cheap throw away remarks like "use mirror-lock up".

So you use mirror lock up with every handheld shot then?Did you even know that a tripod is needed to use mirror lock up?So you are gonna shoot people & sports & EVERY DAMN THING with tripod & mirror lock up?

In the film days (only 10 yrs ago) photogs were stricter with themselves wrt to technical issues like reciprocity failure and mirror vibrations.

But nowadays anyone with a digicam calls himself a photog. Hence your ludicrous nonsense.

Which explains why you don't understand the issues. If shutter vibration is an issue, you somehow can't fathom the problems associated with shutter AND mirror vibration?

Finally, since you can't fathom any of the above, I wouldn't expect you to understand the implications of seeing what the sensor is seeing as opposed to seeing what the eye/lens is seeing.

@Preternatural : wow, and you call others 'ignorant with no understanding of photography' ...

Well, thank you very much for explaining my job to me. I must have missed so much not having your insight for the last 12 years I've been a professional wildlife photographer ... Gee, why am I using bulkier, heavier, more expensive conventional Canon DSLRs ?

Well, I'll tell you why : because the files ultimately outperform anything I've seen from Sony & co, hands down. And I'll tell you another secret : Sony is just not an option in pro nature & wildlife --> to my knowledge, there's not even a single colleague using Sony.

As far as I could see, A7S and the other higher res cameras perform equally in sane ISO levels.

There is one area missing in this test. One can argue that if an X amount of noise reduction is applied to all images, and then they are normalized down to 12MP we can achieve better results with 5DII & A7R. I'm speaking of ISO levels of 6400 and lower.

I think he means what he says. 6400 and lower. 12MP @ISO 3200 from A7s vs A7R + NR and then downscalled to 12MP. I also think A7R will be better because it can easily sacrifice some details in NR process which would be lost anyway from downscalling.

By lower ISOs I mean the normal range 1600 to 6400 that the noise level is noticeable. I think when you do NR on a higher res image you can do better in terms of the granularity of noise detection that you can't do with a lower resolution. I can sure put it to a test!

@maziarrezaei: Ok, I see what you're saying now. I just tried this very quickly and don't notice anything too different from what our results already show. Namely, the A7R still showing a bit more detail even when downsized, but a tad bit more noise in the shadows (and I mean marginal).

This is with NR & sharpening to (my) taste in Lightroom. If you get around to doing this yourself, do let us know your results. I'd be curious.

I haven't heard too much discussion about what I feel are the most compelling combination of features of this S cam - smaller file sizes, silent operation and massive dynamic range. The high ISO performance is a nice bonus too. Recently I switched from a 5Dlll, routinely using the 12 mp small raw feature for weddings, to a Sony A7r for people, using both Sony glass and Leica lenses. Even with the Leica glass and manual focus the A7r is as fast and intuitive as the 5Dlll at about half the weight. But the A7r Howitzer-like shutter is so noisy that it began to ruin the fun of shooting it. Then along came the S. THIS is perfect for me and could be the ultimate "people cam". Small, silent, non-intimidating with crazy DR and reasonable file sizes. There's no need to rip this 12 mp camera for low res or think it's going backwards in any way. Ripping this camera for it's resoulution is like ripping a great putter for not being able to drive a golf ball 350 yards. I'd call it a bullseye.

Man it seems like a lot of work went into this test merely to show that a camera with ultra high ISO options is better than a camera without those options .....**IF you ever need to shoot at insanely high ISO.** Or am I misunderstanding what this is all about, Rishi?

I cannot recall *ever* needing to use an ISO higher than 6400. What the heck are people shooting at ISO 100,000? What needs are actually met by ISO 400,000+? Why not use a tripod or set the camera on something solid in night photography? (Or do people often shoot soccer/football night games at a 1/1500sec. shutter speed? How many people do so?)

(I'm sure a dozen guys will now attack me and say that they need ISO 100,000+ daily and that I know nothing about anything.)

A lot of work went into reaching this conclusion: ..So the bottom line is that the a7s is average at ISO 6400. (At more moderately high ISOs (6400 and below) ........... A7S will be similar to that of full-frame cameras of its generation.)..

It's not so much the ISO 100,000 setting that's of importance in the year 2014, but how noise free the image is at ISO 25,600 that's important. Here the Nikon Df and D4s best the Sony easily 25600. And the Canon 6D is likely as good as the Sony A7s--but this Canon wasn't used for this test.

There are all sorts of reasons for high ISOs. And realistically shooting at ISO 6400 was unheard of in say the year 2005.

It's hard to use a tripod in every situation, for example on the street at night, on the subway, in a small theatrical venue, say a club. So it's not simply about sports at night.

No, it's not useful to my current photography, but then having the option would open up entirely new facets of photography to me. I can't take my Nex7 outside at a quarter moon and so much as hope to get photos of wildlife unless they're asleep. Sure I can use a flash and get 1 chance at a photo, not counting the subsequent photos of animal anuses as they head for the hills, or I can go ultra high ISO and completely silent shutter and take lots.

Dimly lit events? Concerts? No more need to push in PP to salvage a useable shutter speed. No need for an obtrusive flash.

Pretending that the option of shooting at extremely high ISO is useless to all only speaks to the ongoing trend of placing technical image quality over content and, if this site's comments are true, evidently over getting an image at all.

Give me a break. Anyone that had this capability on hand will absolutely find a way to use it.

HowaboutRAW: Do you have any evidence to back up the claims, such as these, you make:

"It's not so much the ISO 100,000 setting that's of importance in the year 2014, but how noise free the image is at ISO 25,600 that's important. Here the Nikon Df and D4s best the Sony easily 25600. And the Canon 6D is likely as good as the Sony A7s"

I don't share my raws, but the testing I've done confirms this point, you can play with studio scenes here.

The point is that in shadows, at ISO 25600, the Sony has typical Sony cyan and magenta banding--that banding is the big problem. Grain is something else.

And the D4s has a bit less grain at ISO 25600, but most importantly zero magenta and cyan banding and/or blotching in deep shadows at that ISO. For the D4s the blotches in the shadows don't really show up until ISO 50,000. The Df is almost as good as the D4s.

The A7s is a good high ISO camera, like the Canon 6D, but it's not the king of the hill for readily useable high ISOs. (Above ISO 100,000 I really have no idea, since it's not realistic to shoot there with any of this gear.)

You obviously are a simple cam person & shoot in none too challenging situations. Plus, you do not know your photography much.

During the film days, PJs used to talk about the "need for speed" & use ISO 800 film, even push it to 1600 even though grain & colour suffers.

For professional shooting lighting levels we go above 6400 all the time. I've had shots that go to 10,000, 12800, 25,600 requiring extensive manual noise reduction work. Such as shots of the President of my country at night (no flash possible).

Need for speed involves understanding that shooting without flash often gives the best, natural results. Cue concert/theatre/dance performances. Even with flash, the most skilled photographers use fill flash at the lowest most imperceptible levels for a natural look. You want as much of the ambient light to fill the shot.

I shoot night aerials a few times each year and 6400 iso good for that, I have gone to 12800 just to see what it's like. if I can shoot at night from a helicopter at 6400 iso what is that needs 100,000iso and more? Never mind the noise where did Sony hide the colour, highlight detail and tonal gradation?

Try shooting available light indoors in a dark restaurant, theater, subway station, and you'll quickly see why beyond ISO 6400 can be of help.

Up in a plane or helicopter do you have to worry about focus and stopping down to get a bit of depth of field? No, you just need shutter speed to freeze movement and you can leave a lens open. It's entirely different when you're only 5-25 feet from the subject.

As evinced by this Seattle night scene, there's not a lot of shadow to peer into from aerial shots at night, another big difference than when shooting indoors, where directed light can cast shadows and you want to be able to shoot what is in the shadows or at least not under direct illumination.

Yes, the silent shutter is great. One must use it carefully though, as it's prone to rolling shutter.

As for the blotchiness: in our own low-light studio comparison at ISO 25,600, the Nikons fare worse in terms of blotchiness than the A7S. Note that the Nikon Df and the Sony A7S were shot at the same focal plane exposure in the comparison linked to above; yet the Df has more of this blotchiness (assuming I understand what it is you're referring to). The D4S does as well, but received 1/3 EV less focal plane exposure, so is perhaps not as directly comparable as the Df/A7S comparison.

And by the way, the D4S will be added to the night scene ISO comparison soon.

For the money the A7r is a well featured DSLM camera Vs. the other so called Pro DSLR cameras. Adding the 100 adapters i have for legacy lenses and my Sony FE lenses; my image quality has been outstanding. True i use tricks, always focus with DMF, always use a polarizer filter to add help too the Contrast AF focusing system. Throw away the plastic sunshade and get a collapsible 55mm rubber for using Polarizer filter. Shooting great video, I am now wishing that websites upgrade their obsolete submission protocols to take 25 meg files or 1080P video on YOUTUBE or others. Still my ISP cannot handle more than a 10 meg jpeg image, so YOU SEE that the cameras are light years ahead of the web services already! Regards, Don@Eastwestphoto

The A7r is all about resolution, but I do wonder how the A7 would have fared in a similar comparison. In some respects it seems the more "all rounded" package the A7 offers is somehow being lost to the extremes offered by the 7s and 7r.

My biggest complaint with the Sony cams is that they are mirrorless.... yes.... I know the advantages, but the disadvantages outweigh the advantages in my book. Being at the mercy of a monitor to know what is coming through the lens is a not what I would call a great method for shooting. Yes, I use ML so I can get full histograms while shooting using a monitor. But at the end of the day the only real way to see what is coming through that lens, outside of long-exposure photography, is to look through the lens itself with your eye. Unless Sony has recently put in screens that can display full RAW dynamic range, which I'm certain they haven't, you are at the mercy of a monitor that cannot even display full sRGB, let alone ProPhotoRGB, and certainly not RAW.

Well.... since I actually work in the film/digital video arena. And more than that, own an 8500 sq foot sound stage and shoot regularly on RED. Yes, I could say I'm intimately familiar with the process. I'm talking about still photography where you have the luxury of time dealing with a single frame.

If you've got the luxury of time and a still subject why does it matter either way? A camera with no viewfinder at all (read: mirrorless with manual focus assist) would be at least as suitable (I'd say more) to those circumstances as an optical viewfinder.

But turn that around and take away the luxury of a still subject and ample time and you're SOL if you completely miss exposure early.

I use my screen for dialing in my focus. Then shift to optical/mirror viewing so I can see all of the light as it is coming through the lens. I don't like the limitation of the screen's ability. Once screens become wide gamut, it will likely be less of an issue.

And when you look through the lens, you are seeing wide open aperture, which doesn't accurately render what the final image will look like. On the mirrorless, the screen is showing you *exactly* what the final image will look like, with the aperture set as the final image will be. I have not seen any issues with my NEX-6 and color rendition. And with focus peaking and 9x zoom, my manual focus old minolta lenses are fun to use and accurately focused. My eyes are not getting any younger, and looking through the glass is definitely not all people think it would be when you have focus zoom and peaking available.

I am having fun picking up old lenses at garage sales or ebay for pennies on the dollar and getting the matching lens mount adapter. I have a huge selection of nice lenses now, and I've spent less than $500 on, in total.

Superchalupa brings up a great point about aperture that people like Dester forget to understand.

Thanks for sharing.

Look we get it Dester, you shoot canon and decided to mention something you don't like about Sony and we all hope viewfinders improve. There will come a day when the resolution and readout speed of a viewfinder is equal to that of the sensor that feeds it.

2014 is a landmark year for photography. The Olympus omd1, panasonic gh4, fuji xt1, and Sony a6000 are all incredibly fast and cheap cameras for what they offer.....and canon is no where to be found (yet - we all want them to) blazing a trail alongside these companies.

I'm not pounding the Canon drum... I'm agnostic when it comes to manufacturers. Cameras are purely tools to be used. Obviously the camera aperture is wide open when not pushing aperture preview. But to say your screen is showing you EXACTLY what you are capturing is utter nonsense. No screen can display what your aperture is capturing. That includes Wide Gamut pro monitors like Eizo. My point is that I like to see what a screen cannot.

Let's hope that monitor technology finally catches up to sensor technology.... because they are worlds apart right now.

Yep A7S is 1-2-3 stops better than Canon or A7R after ISO51000, butI think this advantage useless. IQ is already so bad, that image is barely usable.For me it would be much important to have 2 stops cleaner image @ISO6400 or 12800. It would extend the usable ISO range.On the contrary, what we have now is comparison of different sorts of crap. Yes, one crap is twice as good as the other, but you know, it is still crap.

Amen. I am still trying to figure out why cameras need ISO levels above 12800, especially those not targeting professionals who might occasionally need that capability. I suspect it's because the manufacturer wants a competitive edge in the Specs. (My camera can shoot at ISO 400,000+ and yours cannot! I win.)

It is purely marketing. Lots of non-photographers coming to the market and manufacturer must justify the price/size/weight difference comparing to the P&S. First, in order to push p&s sales (because of cell-phones), they pushed the P&S ISO up to DSLR's level, although max acceptable ISO is still ~400, now they are pushing DSLR's "sensitivities".

I find it amazing how narrow minded some people are that are supposed to be working in a creative field. Just because high ISO does not give you any advantage to how you photograph does not make it worthless. Event photographers, street photographers and documentary photographers would all probably love good usable high ISO camera. You might find some of these photographers also have a different opinion of what quality is then you. I personally find this camera very interesting and look forward to see how it performs in real world examples.

DxO has previously verified* that Sony partially cooks their RAW data for noise reduction purposes — so rendered files "appear" to have less noise and better performance characteristics.

quote: "If reducing noise is so easy, why is it not always applied? Well, there is a price to pay: averaging pixels increases SNR, but introduces some correlation between pixels. This creates a grainy aspect to the image which is often as annoying as noise itself. Moreover, if pixels are blindly averaged, fine details may simply be erased."

a similar high ISO benefit could be achieved in post using non-sony sensors, with the exception that the photographer selects which regions and compromises are applied. as DxOmark hasn't broken out how different RAW files from different sensors are treated, comparisons of this kind appear much like RAW batter to cooked fudge. while fudge tastes great, i'm not sure DxO's recipe is absolute.

This was on much older Sony sensors, like the A900. DxO tests every camera for signs of raw noise reduction and reports it as an open circle on the SNR/DR charts when found. Based on the charts they did not detect noise reduction on the A7s. Interestingly they did on the Canon 1DX.

You can download the RAW files yourself & apply NR to see if you can get any real image detail out of the highest ISO shots. See if you can match the A7S in terms of shadow detail retention at ISO 204k & 409k.

DxOMark's Full SNR curves show that the pixel-level SNR of the A7S at ISO 409k is higher than that for the 5D Mark III in shadows. At some point (brighter tones), the SNR curves cross, & the 5DIII ISO 102k takes over with higher SNR. Naturally, as these brighter tones are photon/shot noise limited & therefore benefit from the longer exposure at ISO 102k.

Now, those are pixel-level SNR curves. Normalization will shift the ISO 102k 5DIII curve to the left, which'll move its crossing point (with the A7S 409k curve) to the left. In other words, the 5DIII ISO 102k file will be better at slightly darker tones than what the crossover point currently suggests. But I doubt it'll move that much, & so A7S 402k shadows will continue to show a 2 EV advantage.

But let me repeat: this 2 EV advantage is really only for darker tones at the highest ISOs (204k & 409k, judging from my visual tests). The advantage starts to decrease as you go to brighter tones.

That's no easy task, so the A7S should be applauded for what it's doing here. Whether or not this advantage actually makes a significant difference to your type of shooting is another matter entirely, of course!

I'll see if I can get my hands on normalized full SNR curves to correlate with the visual analyses presented in this article.

After a quick look at the RAW comparisons of the A7s and the 5D3, I must say it l0oks like we are splitting hairs here. They all look pretty similar to me with the 5D3 perhaps retaining more highlight detail. The thing is that on many shoots I have been more than happy with my 6D's performance at 25000iso. I am actually just blown over by the quality of the images...I have even made A2 prints of theatre images and the quality is just superb ,but I am sure this quality can also be had from Nikon, Sony etc...I even bought DXO because of the many times I find myself using 25000 iso and after my initial test DXO looks like the king of noise reduction, imo only of course...We are living in good times!

A lot of comments read like: Yes A7S makes sense at 6400+ ISO but who shoots that? The other cameras beat it soundly at base ISO.

But similarly, who needs all the detail of a FF camera at base ISO? You put it on a monitor, even a 4k monitor, that's a lot of crop. You print it out, that's a lot of wall space. The A7S is fractionally less wall space and fractionally less cropping. That's not much of a sacrifice for the added sensitivity. If I have all the light in the world and reach for an A7S instead of an A7R, how much practical difference does it make? I say little to none. In bad light, it makes a big difference. You guys have it backwards.

That's a pretty silly argument! Canon has the clear advantage up to ISO 1600, it is about a draw from 1600 to 25600 with Sony having a VERY slight advantage strictly defined by noise but Canon having clearly superior all around image quality due to highlight performance, with Sony finally pulling ahead of Canon over 25600. 25600 is pretty well up there! So Canon's superiority goes well beyond "base ISO" and it's only in the realm where both look terrible that Sony has an advantage.

So you're saying when they're both great, one is better than the other but when they're both bad, neither is useful?

"Good Enough" more than describes low ISO performance on all of these cameras. It's getting to the point where people want more quality than their eyes can see. I don't need good sound reproduction at 40,000 hz, I can't hear it. I don't need more detail in a shot than I can see on a 4k screen.

What I'm saying is ISO 25600 is not "base ISO" or "low ISO". It's very high, Canon has a noticable advantage up to that level, 99% of images will be made in that range, and neither camera offers image quality over ISO 25600 to make venturing higher worthwhile.

I feel the opposite. Who cares how the camera performs at base ISO? My cell phone does pretty well in broad daylight. FF exceeded my image requirements at base ISO since it's digital inception. All I want is more sensitivity and versatility.

@mosc: Shooting at high iso is not the only reason why photographers use FF cameras. Cell phone cameras!? I wouldn't want to see my wedding photographer shooting the wedding with his iPhone or Lumia 1020 :D

I think this test is a good start to show where the high-ISO advantage of the D7s should be expected: dark tones at exposures for very high ISO.

But, there may also be some sensitivity difference at all ISO settings for very large aperture lenses. This is because it is easier to make large pixels accept extreme ray angles than small pixels. So, I would like to see this test also conducted at f/1.4 to see if there is a noticeable sensitivity difference for bright tones at that f-stop.

The results of this testing clearly reveal that the A7s' strengths are in (low) read noise that comes into effect particularly in shadow areas of the image.That being said, I wonder whether the TRUE advantage of the A7s sensor might be in allowing to significantly underexpose images and to boost shadows in postprocessing to much better effect than would be possible with other cameras. The benefits of this would be: you could use much higher shutter speeds, particularly when you want or need to avoid motion blur (moving objects inavailable light) or when you use non-stabilized lenses and want to avoid camera shake blur.

In other words, could it be that the A7s may provide much more leeway for boosting underexposed image areas in PP and this being the *true* (albeit not yet systematically explored) advantage of the A7s over its A7 siblings or other FF cameras?

Again number of pixel has very nominal effect on the final output noise level. Hopefully this will stop everyone complaining about more megapixels. this camera is simply no better than the 36mp sony or the 23mp canon sensor for the same size output.

If I had money, I might buy one, but I'd be more inclined to buy a D4s or Df--they're both better high ISO cameras. I'm still glad to see Sony releasing this camera. Hope they do an A99 II with this sensor.

HAR, I never said downsampling reduces noise. It actually reduces detail. to my eyes, at iso 25600, comparing the 7s to downside 7R is see no difference in noise. now, would be very interesting to print both at 300 dpi at 12x18. I bet you the A7R image would have more detail for same noise, or less noise for same detail, once processed from raw.

It's a myth, try it with any setting in Photoshop. It may be what the math claims but when the results are that bad, and they are, then the math is suspect.

S/N ratio enhancement claims: My guess would be that the program counting signal is confused. This is often the case with this kind of engineering estimation.

The problem with the downsampling idea is that somehow downsampling would have to be able to readily identify noisy pixels in the process.

If removing noise were that easy, then NR would be real easy in the camera. And as you know it's not.

Now what sort of works, tossing about 90 percent of the data from a noisy image shot with many pixels may be a bit better than shooting with fewer pixels, but then you're left with a tiny thumbnail--that's pretty blurred.

Really, please try downsampling in detail, it doesn't work.

Perhaps something will radically improve in the understanding of this engineering in say 10 years--then maybe this will work.

Assuming same sensor size, more pixels = smaller pixel. Each pixel generates read noise, thus more pixels per area = more noise per area.

Read noise is not bothersome when the signal is strong enough for shot noise to overwhelm read noise. But for a weak signal, read noise can be very significant.

High ISO means that the signal is weak. It is simple physics that sensors with smaller pixels will generate more noise at high ISO (with other variables being more-or-less equal).

Plus there are a few other potential sensitivity advantages of larger pixels. For example, larger pixels are less obstructed by circuit elements and may thus produce slightly superior QE than smaller pix.

Yeah, spot on. Except that sometimes sensor designers will be able to decrease read noise per pixel in the higher resolution camera, in which case read noise per area does not necessarily have to be higher. All you have to do is decrease per-pixel read noise by sqrt(n) for a n times higher resolution sensor to make read noise per area the same. In which case normalized comparisons will show little to no noise differences between the lower res & higher res camera.

Therefore, in practice, lower resolution cameras don't always offer the advantages they're meant to. Although in this case, the A7S does - but only at very very high ISOs. You'd be hard pressed to see normalized differences between the A7S and A7R up to ISO 12,800 - have a look yourself in the widget.

Above that ISO - shadows see a significant benefit with the A7S' lower aggregate read noise (3x less # of read events) and potentially lower resulting quantization error due to the higher conversion gain.

Also, re: your point about potentially higher QE - this advantage is sometimes not as fully realized as it might otherwise be had gapless microlenses not been invented to help the potential light loss due to increased inter-pixel spacing.

HowaboutRAW: It's not a myth; one needs to go no further than our own studio scene to see this.

Have a look at this particular comparison of low resolution cameras on the left vs. high resolution cameras on the right at ISO 6400.

Although the low resolution cameras have lower noise at native resolutions, the leveling field evens out as soon as you click the 'Print' to normalize the comparisons by downsampling all cameras to the same (8 MP) resolution.

It can't get any clearer than that. Continuing to argue against what the visual results clearly show & the math dictates is just misleading our readers.

For example the ISO 256000 raws from the A7r and A7s with the former downsampled. And that A7r is doing an okay job, but the A7r result is noiser--just as one would expect from the full sized image.

What makes you think I've never tried this?

I don't click "print" to downsample, I downsample in Photoshop. You can't make the A7(D610) shoot higher ISOs like the D4 by downsampling.

Now there is some possibility that "print" is introducing some other factor, and that, as a solution to the claims of NR, I'm open to. For example printing to paper, beyond 300ppi, does help with noise reduction.

I checked again. Using the A7r and A7s ISO 25600 raws from the Seattle sky at night from the DPR test.

With the raws down-loaded, I extracted them to 8 bit tiffs with the same NR settings in ACR 8.5, within PhotoShop CS6.

Then I downsampled the A7r tiff so its pixel dimensions were the same and, I believe 4240 across. Result: The A7r tiff had a bit more grain, and much much more cyan and magenta blotching than the A7s tiff. (Let PhotoShop use the first resampling algorithm. I believe there are 6 to pick from.)

How many times do I have to repeat the test? Downsampling does not have some magic way of sorting signal from noise and holding on to signal. Now for that ISO, the A7r did surprisingly well for grain, not for blotching though.

You claimed downsampling does not reduce noise. That's completely incorrect, which can be shown time and again simply by hitting the 'Print' button (which down-samples the image to 8MP) in our studio scene.

This article was looking at any tangible gains w/ the A7S over the A7R - in normalized comparisons - due to the larger pixels of the A7S and/or any other optimizations to the sensor/signal processing.

The conclusion was that differences exist - at higher ISOs - where simple normalization does not reduce noise enough to bring the SNR of the higher resolution sensor up to that of the lower resolution sensor.

Clear now? Downsampling reduces noise, but in this case not enough - at the higher ISOs - to match the performance of the A7S.

Again, that was the entire point of this article, & presumably one of the reasons behind Sony making the A7S to begin with (video considerations aside).

We even talked about reasons for why the normalization might not be enough. E.g. the A7S might have the following going for it: lower aggregate read noise of 3x fewer pixels, potential QE increases, possibly decreased quantization error due to higher conversion gains, etc.

But as for reasons why the A7R can't keep with the A7S at higher ISOs, it's definitely not that 'downsampling does NOT reduce noise'. That's just incorrect, and a misleading statement. It's that downsamping/normalizing does not reduce noise enough to provide the same level of performance as the A7S for very, very low signals. Likely because of one or more of the reasons in the previous paragraph.

Let's make it clear... shooting "4K video", most of which isn't actually 4K but UHD (but I digress) ≠ superior video. There are so many factors involved including file compression, color compression, artifacting, motion estimation in compression, shutter roll, etc. In fact, I'd pick a 1080p or 2K camera with a universal sensor shooting RAW over a 4K camera with decent compressed image.

I am frequently hitting ISO 6400 and still wish for higher IQ at those and higher levels, I would prefer higher IQ at ISO 100 though, thats more important to me, but hand holding at higher ISO's is nice to have.

The results are impressive....all the cameras have decent high ISO performance. For my purposes I would take the A7R with it's higher resolution and greater dynamic range at lower ISO's. For me, I have pretty much zero need for any ISO over 6400, and in actual use rarely use anything above 3200.

It's funny...I kind of look at stratospheric ISO ratings much the same as stupidly high fps ratings....unless you have a very specific need it's a completely useless rating. 90% of the people who say they 'need' 10fps don't....same things goes for these crazy high ISO ratings.

That said...choice is good and Sony gives you three options with the A7 lineup...

6 out of 39 shots have had digital boosting in post-processing. That's 15% of the shots. So, no, this is not an 'ISO non-boost vs boost pp shootout'.

You can even ignore all the files boosted in post-processing and still come to the same conclusions we have. That is: the A7S ISO 409k shot has shadows with similar noise levels as the 5DIII's ISO 102k shadows, but this advantage drops as you look at brighter tones or compare lower ISOs.

An 'ISO non-boost vs boost pp shootout' would hold the focal plane exposures exactly the same and look at high ISO images vs lower ISO images with appropriate digital boosting. In such tests, you will see lower performance of certain cameras - such as Canon DSLRs - because of high levels of electronic noise downstream of ISO amplification. But that is another matter entirely.

"who doesn't know the larger pixel can handle higher isos in low light with less noise than smaller pixels?"

It would seem you missed the point about the normalized comparison?

Yes bigger pixels collect more light, but normalizing the comparison is a way of simulating equal resolution across the A7S & A7R. Then the comparison gets interesting, b/c the A7R's pixels have to theoretically have sqrt(3) less read noise than the A7S' pixels to match high ISO performance after normalization. That's b/c, generally speaking:

All else held equal, a n times higher res sensor has to have per-pixel read noise that is sqrt(n) times lower than the per-pixel read noise of the lower res sensor.

This is because extra aggregate read noise from reading more pixels. And this says nothing about other factors at play: readout speed, QE, etc.

So the point is actually far more subtle than your simple 'bigger pixels are better' argument. And so we wanted to empirically test the performance.

btw, normalizing downwards (downscaling) is not the only legit means to compare fidelity of details (it actually conceals it)but rather normalizing upwards (upscaling) far more reveals if the finest details are captured with the least distortion as well as least noise intrusion (plus poor NR algorithms that just 'mash' (obliterates) fine details. (strictly very low light scenarios)

it isn't uncommon for higher mp sensors (sony/nikon) to offer LESS resolved finer details, grossly distorted by poor NR or obscured by massive cluttering of elevated noise in high ISO image capture in very low light. resorting to very low 12mp doesn't help on retaining fine details even if turns out so much cleaner with less noise but resolving much less.

right now, Sony is opting to go two paths:low-mp 12mp and high-mp 24/36, each making significant compromises in resolving power of 12mp ff with superb low noise iq in high iso low light, and unacceptable noise in low light of 24mp aps/36mp ff with dubious gains in resolving power.

Canon has opted to go down the middle path compromising less on either, with 18mp aps/ff as well as 21/23mp ff.

fuji's multi-sized pixels was still a mono-iso sensor typeit still faces limitations of dealing simultaneously with both high contrasty bright wide DR scenarios AND very low light low contrast scenarios.

one could essentially lump all mono-ISO systems as already hitting their limitations to capture full range of luminance of any/every lit scene we encounter in the open.

it's long overdue to design multi-ISO sensitive capable sensors, to at least match or exceed the way we 'see' (variable dynamic sensitivity; not fixed static ISOs in a single capture; not multiple capture)

No, you don't upscale the lower resolution camera to the higher resolution to compare noise. The higher resolution camera starts at a disadvantage for pixel-level analysis b/c of its smaller pixels. For comparison to a lower resolution camera, you simulate the pixel size of the lower res camera by downscaling. This is an algorithm available to you that effectively simulates what would have happened in the hardware had the signal from n pixels been 'binned' to 1 pixel - by adding together the signal from the n pixels just as they would've be 'added' automatically in hardware had there been no subpixels within that region.

If you upscale the lower res camera image, what on earth are you simulating? Dividing up 1 pixel into n pixels? How's an algorithm going to do that - that is, create information where none is available?

Think of it this way: you start w/ a low noise, low res image, and a high noise, high res image.

If you upscale the low res image, its noise stays the same, it doesn't really gain any res, and so your comparison leaves you right back where you started: a low noise, low res image, and a high noise, high res image.

If you, OTOH, downscale the high res image, its noise decreases, and its res matches (our supersedes) the low-res image. So you now have your low noise, low res image, and a new image with potentially the same, or some degree worse, noise, with the same or better res image.

Which scenario above do you actually learn something from? Key in that statement is 'potentially the same, or some degree' worse. That's what you learn by opting to downscale, not upscale. If you upscale - you already know the answer to begin with when it comes to noise.

Also - upscaling typically makes the images incomparable. The noise is different and the scene detail resolved is different. Downscaling removes one of those factors (scene detail resolved) so you can focus on the noise differences.

In general - you don't change two variables at the same time. You control for one, while assessing the effects of the other.

As for your statement: " unacceptable noise in low light of 24mp aps/36mp ff with dubious gains in resolving power."

(1) Unacceptable noise? This entire comparison shows that the 36 MP A7R holds up quite well all the way up to its max ISO (25,600). It's not unacceptable at all. It's actually better than the 22MP Canon 5D Mark III, so I have no idea what point you're trying trying to make about Canon & its 'middle path'.

(2) 'Dubious gains in resolving power'? That's demonstrably an inaccurate statement, as a simple MTF analysis will show you. So will the images above (if you select 'Native Resolution'), by the way.

Note I'm not saying upscaling comparisons are entirely useless for all scenarios. For example, you can make a case to upscale to compare how much effective resolution a higher resolution sensor is providing with a given lens (which may not have enough resolving power to take full advantage of the higher resolution sensor, e.g.). Or, generally, for comparisons of that nature.

But for noise comparisons, it makes little to no sense for the aforementioned reasons.

Thanks trustya - that's appreciated. If I can help even one person think through a concept and get it for themselves, that's a good ROI in my book. I also learn something in the process sometimes - the underlying source of the misconception. And questioning why you believe what you believe is great - you either reaffirm what you believe or you consider changing your point of view. One should always be open to the latter.

Thanks for adding this comparison, next to the "standard" comparisons. I hope DPReview will add more of these kind of comparisons. It really helps to get grips on the value of technological advance for your photography or when selecting a new camera.